The town centre was designed by James Wyatt in 1780, in the Georgian architectural style. Its layout follows the medieval principles of urban design introduced by the Normans in the 13th century. The design for the town was commissioned by the Lord Sligo of the nearby stately home, Westport House, as a place for his workers and tenants to live. A particular feature is the incorporation of the river into the composition, contained for two blocks by low stone walls producing, on each side of the river, attractive tree lined promenades (The Mall) with several stone bridges over the river Carrow Beg. The layout further includes several tree lined streets, addressed by the narrow fronted commercial buildings typical of Irish towns, though with many here remaining of a singular refinement and charm. Some modern interventions, such as the Garda station, are less successful in maintaining the original continuity of the urban fabric.
It was the home of the pirate chief Grace O'Malley in the mid-to-late 16th century.
The famous pilgrimage mountain of Croagh Patrick, known locally as "the Reek", lies some 10 km west of the town near the villages of Murrisk and Lecanvey. The mountain offers a striking backdrop to the town. The church on the summit can just be made out with the naked eye from Westport.
Westport is a popular tourist destination and scores highly for Quality of Life. It has also won the Irish Tidy Towns Competition three times in 2001, 2006 and 2008; in 2012 it also won the Best Place to Live in Ireland competition run by The Irish Times.
Westport originates and gets its name, in Irish, from a 16th-century castle--Cathair na Mart (meaning: The Stone Fort of the Beeves or The City of The Fairs)--and surrounding settlement, belonging to the powerful local seafaring Ó Máille Clan, who controlled the Clew Bay area, then known as Umaill.
The original village of Cathair na Mart existed somewhere around what is now the front (East) lawn of Westport House. It had a high street, alleys down to the river and a population of around 700. It was moved to its present site in the 1780s by the Browne family of Westport House, who also renamed it Westport.
Westport is designated as a heritage town and is unusual in Ireland in that it is one of only a few planned towns in the country. The design of the town is attributed to James Wyatt, an English architect. He also completed Westport House, the stately home of the Marquess of Sligo and designed its dining room. Westport House had originally been built by Richard Cassels, the German architect, in the 1730s, on the site of the original Ó Máille Castle. The dungeons of the Ó Máille castle still remain. The most notable feature of James Wyatt's town plan is the tree-lined boulevard, the Mall, built on the Carrowbeg River. Since the late 20th century, Westport has greatly expanded with several new estates. Some of the most populous estates are: Springfield, the Carrowbeg Estate, Horkans Hill, Cedar Park, Fairways, Knockranny Village and Sharkey Hill.